code: def testBFS(self):
      g = Graph.Tree(10, 2)
      vs, layers, ps = g.bfs(0)
      self.assertEqual(vs, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
      self.assertEqual(ps, [-1, 0, 0, 1, 1, 2, 2, 3, 3, 4])
  
file_path: python-igraph/tests/test_iterators.py
imports: import unittest
  from igraph import Graph
label_desc: Use image node_id 1 for calling the IteratorTests obj's underlying member method code with example usage: obj.testBFS() without return types